Characterization of Nuclear and Membrane Progesterone Receptors in Bovine Endometrium.
Notice bibliographique
Résumé
Progesterone (P4) is essential for maintenance of pregnancy and also plays an important role in the timing of luteolysis in ruminants. The time from estrus to luteolysis is regulated by P4 since a) treatment of cows with P4 early in the estrous cycle results in premature luteolysis and b) delaying the action of P4 on the endometrium by the use of an antagonist delays luteolysis. However, the exact mechanism(s) of action of P4 in the endometrium is still not known. Nuclear progesterone receptors (nPR) occur naturally in A and B forms, which result from alternative promoter usage of the same gene. The two PR forms are hormonally and developmentally regulated. The specific role for each of these two PR subtypes in the regulation of endometrial function is unclear. However, the existence of elaborate mechanisms regulating their production suggests that the relative levels of PRA and PRB in cells is critical for appropriate cellular response to P4; for example in human parturition when there is no change in plasma P4 concentrations. P4 can also have non-genomic effects and membrane receptors (mPR) in the epithelial cells of the ruminant endometrium have been shown in sheep and cows, but no detailed studies have been performed. The hypothesis for this study is that changes in mPR and/or the ratio of PRA/PRB during the estrous cycle in the cow are responsible for regulating endometrial function, including induction of luteolysis. The objectives of this present study are to determine if changes in PRA, PRB and mPR occur during the estrous cycle. Endometrial samples, from uterine horns ipsi- and contra-lateral to the corpus luteum, were collected during the early, mid and late stages of the estrous cycle from cows (4 cows per stage) at the slaughterhouse and snap-frozen until analysis. Measurement of mRNA for PRA and PRB by RT-PCR has been established and the results show that both isoforms are expressed at all stages of the cycle. Quantitative PCR has now to be performed to determine if changes occur during the cycle. Protein expression (measured by Western blotting) shows PRB and PRA at all stages of the cycle. There was a higher expression of PRA in the ipsi-lateral horn (P=0.05, n=4) but no difference was observed at the different stages of the cycle in either horn. Further studies are in progress to determine if changes occur in the different cell types of the endometrium. Preliminary data show that mPR? mRNA is present in the endometrium throughout the estrous cycle. These data show that mPR and the different isoforms of the nPR are present in the bovine endometrium and could play an important role in its regulation. This work was supported by NSERC.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,001 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,001 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,002 | 0,001 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».